Fullerene, carbon nanotubes, graphene, graphite and the like are materials composed of carbon atoms. Thereamong, graphene has a structure composed of a single atomic layer of carbon atoms disposed in the form of a two-dimensional plane.
In particular, graphene exhibits extremely stable excellent electrical, mechanical and chemical properties as well as superior conductivity, which transfers electrons much faster than silicon and conducts much greater electricity than copper. This was demonstrated by experimentation since a method of isolating graphene from graphite was found in 2004 and a great deal of research has been conducted to date.
Such graphene draws a great deal of attention as a basic material for electrical circuits because it can be manufactured in a large area and exhibits electrical, mechanical and chemical stability as well as excellent conductivity.
In addition, generally, electrical properties of graphene change depending on grain orientation of the graphene of a predetermined thickness and thus the graphene exhibits electrical properties in a direction selected by a user and, as a result, a device can be easily designed. Accordingly, graphene can be effectively used for carbon-based electronic or electromagnetic devices and the like.
In general, application products such as display devices require a transparent electrode and extremely thick transparent conductive oxide films are used in order to maintain requirements for such a transparent electrode.
However, such thick transparent electrodes may be inapplicable to deposition on plastic substrates to manufacture flexible devices and displays and may be unsuitable in terms of transparency and low surface roughness. Thus, there is a need for an alternative to this.
Meanwhile, recently, silicon oxide dielectrics are applied to analyze device properties of graphene. In a conventional case, since p-type doping is obtained by doping the substrate, an undoped form obtained by additional heat treatment or self-assembled monolayer coating is used.
In addition, surface modification could not be generally realized because there were cases in which heat-treatment cannot be conducted or a self-assembled monolayer cannot be formed on substrates other than silicon oxide. Accordingly, there is a limitation in doping effects of graphene and an approach to solve this problem is thus needed.